Injection engine fuel



Sept. 12, 1950 G. H. DENISON, JR., ETAL 2,521,693

INJECTION ENGINE FUEL Filed May 2, 1946 a9 6.) FEED g Q;

mfi WATER \f k A ,/9 7 WATER 4577:4719 CAUST/C w; 0 /8 *22 E37 a All? F 23 8 24 43, as g u I T L 25 1 WATER 14670 AC/ 34 7 TREA TOR 27 4 PRODUCT 29 v 30 5 STORAGE TAN/( 4 r 4 32 L 44 r a 33 6 I INVENTORS. George H. Denison, Jr.

John' E. Hanson ATTZRNEF l atented Sept. 12 1950 Berkeley, Califi, 'a'ssigno'r's 'to-"California Research Cor-poratiom San Francisc'og Gatling-a ootiporation of Delaware Application Mayi2, 1946,"Se 'rial No. 6661701 This invention'relates to improvements inf fuels "for injection engines, and especially'to'fuels 'for internal combustion engines of the Diesel type; in which a liquid fuel is injected intothe combustion chamber and ignitedby compression;

and'in certain aspects relates particularly to the modification of hydroc'anbon fuels employed n compression ignition motor service and the'admixture or blending of such modified'fuels'with ordinaryor special'hydrocarbon fuels'of the Diesel type in such a manner as to enhancethe combustion characteristics for Diesel'rnotor purposes.

In the attainment of minimum engine knocking the time interval between'theinstant of'liquid I fuel injection and instant of ignition, referred to as the delay period, should be as brieffas, possible. Generally this delay period'is known to be affected by the type orcharacter of the hydrocarbon composing the fuel. It is likewise known that it may beshortened by-theaddition to the fuel of variousv accelerators or primers.

Such ignitionaccelerators or primers are .me-

I chanically admixed with or dissolvedin the fuel in amounts between 0.1% and 10% by weight of thefuelhydrocarbon.

hydrocarbons generally These substances are oftencostlyland sometimes hazardous to prepare and handle; their uniform and permanent incorporation in the fuel is 00- casionally uncertain, and'in somecases 'the'beneficial ignition efiects obtained are attended by adverse effects of othersorts.

In the present invention,'fuels of high ignition quality as measured byrdecrease in delay periods are prepared by derivation. from the petroleum hydrocarbons which themselves could suitably compose the usual whole Diesel fuel. orfrom hydrocarbons more volatile than the'usual whole Diesel fuel or fractions thereof. This modified fuel is derived inits simplest terms through a carefully controlled partial oxidation of said hydrocarbons under definitely controlled conditions followed by supplementary treatment of the partially oxidized oil designed to produce a composition which is not subject to deterioration in storage and is free from components'adversein their efiects upon'Dies'el engine operation. prepared, the fuels of the inventionarelowdn cost, of consistently high ignition qu'ality,1perma- 'nent and stable in storage, and general-lywithout adverse qualities from the standpoint-of marketability.

The processes of this inventionlprovidefor the preliminary selectionof a suitablev feed Stock .or

treatment of a synthetic or "natural-petroleum fuel or gasoline or kerosene distillate or ordinary 7 1 2 I Dieselfuel "characteristics or a" portion of such 'a-"fuel by 'such means as Willjproduce a suitable "feedstock composed-of hydrocarbons capable upon partial-oxidation in-theliquid phase with air 'or other oxygenecarrying gas of attaining an oxygen facton'of at =least-25l),and treating said "hydrocarbons with an oxygen-containing gas ..under such conditions as will allow it toatta-in saidoxygen factor, "without concomitant increase irr neutralizationnumberof-more than about "1'5; treating the partially oxidized oil with a *stronfg acidic? reagent 4 and" to a" subsequent caustic wash "to "give "a highlystable nonecorr'osive "product f'which maybeiemp'loyed as 'an-injection engine "fuel in and of itself or "'mayb'e blended with one or more "ordinary hydrocarbon fractions to i'pro- "duce a fuel" of the desiredhigh ignition-- and-other qualities. YThe' ch'ara'cter'dfthe'oil'used forifeed is of conz'si'derable consequence i'n'p'roviding a mixture :of

hydrocarbons capable of attaining high oxygen "factors on oxidation and exhibiting-.a generally proportional "increased cetane number value.

' 'In" general; these oilsfsl1ould"be"free fromlarg'e "proportionsof aromati'dring'structures,;asphaltic andresin'ous m'ateria'ls and large. quantities of na'ltural "anti-oxidants and "should contain a grou of relatively volatile hydrocarbons. Straight-run pf'etr'cileum JdistiIIate's "are preferred as initial 'niaterials and such distillates preferably "should be aci'd treated or selectively- 's'olvent refined jbe'fore oxidation for coptimum results. Qils Efc'cntainin'g thigh proportions of :aromatic; rings Tare" lessje'a'sily ca'pableof attaini'n'g high"oxygen factors than are 'oilsof. high paraflinicity, although the treatment of oils ofjhigharomatic content with relatively (strong sulfuric acid for "an e'quivalent chemical reagent 'or"'theirj extraction "with. liquid solvents 'suchja's j li'qllid sulfur .fdioxide phenol, aniline, furfural,

nitrobenze'ne and the, like, in removing aromatic components or .reducing j'their concentration, suffices to improve. theirfamenability tostre'atment in accordance with'the'invention.

,The oxidation step of thelprocess isv preferably carried out .,within the'temperature range0ff 25l F. to- 350 F. and, preferably with the aid of 9. small, amount ,ofseed stock .fromthe preyio us run. .An amount of seedstock betweenebout "0.5% and 5,%., is usuallydesirable. :The oxidation is. continued .for a time not materially 1 longer than is necessarytogive an oil of the maximum oxygen factor attainable and alsotto prevent undue for mation of ,imdesirable side reaction products. In general, the oxidation step is regulated to produce an oxygen factor of at least 250 and a neutralization number of not more than 15. The partially oxidized oil should not be allowed to remain at or near oxidizin temperature for any considerable length of time subsequent to the attaimnent of the desired oxygen factor due to the secondary reactions which continue at the expensef'bithe desirable prodiicti' ,"It is therefore of importance to quickly cool the oil as, for ex ample by quenching with water to a temperature below that at which secondary reactions are rapidly taking place, namely, to a temperature below about 250 F. and preferably as low as 100 F.

It is frequently desirable to wash this-partially oxidized oil with a dilute caustic solution to remove acidic substances and salts or soaps of organic acids before proceeding with the subsequent treatment. A 5% aqueous caustic solution in an amount equivalent to about more than that theoretically required to effect neutralization is preferably used. A materiallyv stronger caustic solution tends to destroy the desired partially oxidized hydrocarbons as does a substantial excess of the caustic. In some cases where acid is not formed on oxidation or is not detrimental, it is advantageous to dispense with the caustic wash and proceed with the subsequent treatment.

Further complete discussions of the steps of partial oxidation, quenching, and caustic washing a chosen feed stock aswell as analytical methods for the determination of oxygen factor and neutralization number are given in U. S. Patents Nos. 2,365,220 and 2,317,968 to Shultze et al. In

preferred and specific aspects, the process and products provided byour invention may be regarded as improvements on those described in said patents involving the discovery and utilization of a, supplementary treatment applied to the products of the patents as initial feed stocks, whereby the high cetane number enhancement capability of the partially oxygenated compounds is substantially retained concurrentlywith a, conversion of these compounds't'o 'a state which is more stable and characterized by an entirely or the charging stock boils within the range I ZOO-450 F. y Y

Pursuant to this invention, it has been found possible and highly important to treat this partially oxidized product with a strongly acidic material to form a stable, less corrosive, and more readily usable product. It has furthermorebeen found that the oxygemcontaining cetane-improvin compounds 'present in this partially oxidized oil and measurable in terms of oxygen factor may. be successfully converted to a superior type of oxygen-containing compounds which are more stable in storage upcn'admixture with certain types of base fuels and which are substantially less corrosive. Furthermore, it has been discovered that this acid treatment to produce a highly stable, non-corrosive cetane-improving compound may be accomplished without'eflecting a substantial decrease in the cetane-improving qualities of the partially oxidized stock being treated. For instance, five per cent of the par- .100 and gave a cetane number increase of 5.7. The loss due to acid treating was therefore 1.7

cetane numbers or about 25% of the cetane improvement capability of the untreated partially some instances show less decrease in cetane improvement capability and in other special cases show a loss in excess of 25% by the acid treating procedure disclosed. However, the partially oxidized stock not given the treatment with an acidic reagent lacks stability and gradually loses its cetane-improving characteristics on storage while the treated stock maintains a substantially constant value. In addition, the untreated partially oxidized stock shows a high corrosivity to lead, while the acid treated stock shows very little corrosion. The lead corrosion test is carried out by immersing a lead strip x 1 x in a beaker of the sample maintained for twenty hours at about 225 F. The loss in weight of the lead strip is noted. The substantial improvement obtained as to both stability with respect to cetane number improvement and decrease in corrosivity is shown on a quantitative basis by the data on comparative experiments given in Tables 1(a) and 1(1)). The concentrated stock used in Table 1(a) was prepared as hereinafter described.

TABLE 1(a) Cetane number stability Treatment of Concen- Ox en Percent cetane Improvement 'trated Partially Oxig Added stock to SCR 1 15 min. 48 hrs. 96 hrs.

None 6,240 2 l2 7 6 1% 1b. H2S04/gal. 8'10 2 11 11 10 1 SCR refers to Southern California Regular Automotive Diesel base having a cetane number of 36.

TABLE 1(17) Lead corrosivity X331 5? Treatment of Partially Oxygen e 0 Lead Oxidized Stock Factor fig ggg Corrosion Waxy Base Ma. None 839 10 158 1% lb. of 75% H2SO4/ga1. 141 10 7 arcane-es 'Ihe resulting fuel was allowed to stand-approximately one month before testingifor cetanenumber increase.

' S OR'refers to Southern California Regular Automotive'Diese base having'a-cetanelnumber of 36.

It has been found convenient to use sulfuric acid in'this step of the process, and its use will be further described. However, strongly acidic substances can be substituted -therefor as noted above; specific conditions of treatment may be slightly diiferent and varied with the various acidic reagent'tovgive optimum results.

In "general, it has been found that between 0.1'and 0.75 lb. of 50% to 98% sulfuric acid per gallon 'of the partially oxidized unconcentrated feedstock is desirable. It has further been found that under usual operating conditions a treatment with about /4 lb. of 75% sulfuric acid per gallon of the feed gives optimum results. A treating time of between'a'bout five and ninety minutes and especially between about fifteen and about sixty minutes "is to be preferred. Treating temperatures up to 95" F. have been successfully used; however, an intermediate range of 50 F. to'85 F. is more suitable and 60 Fjto 80 F. is'preferable. Temperatures as high as 145 F. give serious decomposition of the active octane number improving ingredients. When properly practiced under controlledtemperature conditions, the acid treatment results in a substantial reduction in the tendency of the partially oxygenated hydrocarbons to "cause corrosion, and a substantial improvement of their stability as to their c'etane number improving quality Without substantial'decrease in the numerical value thereof. 'This change is attributed to a change in the constitution ofthe oxygenated compounds'which it has been discov'ered'results in and may be measured by decrease in oxygen factor. Thus, it has'been'ascertained that when temperature is controlled as above indicated, the

reduction in the value of the oxygenfactor serves as a criterion for the maintenance and-attainment of optimum conditions for the acid treatment. Hence, conditions of acid treatment are preferably adjusted to give a reductionof the oxygen factor from 250 or above to to "or less of the original value. Ingeneral, it has been observed that the lower the oxygen factor after acid treatment of the partially oxidized oil the more stable and less "corrosive the acid treated product. It has further been found-that the partially oxidized oil may be conveniently treated with the sulfuric acid in a batchwise manner. For example, it has been found that the temperature may be more readily controlled to the desiredvalue by adding the total sulfuric a'cid employed infour dumps with a cold Water wash between each dump. Thenumberofdumps maybe increased or decreased asdesiredor even combined into one in some cases /in accordance with this invention. The effect of lvarying the many other conditions :underwhichiacidtre'atmentiis accomplished iS-IShOWIl by .Lthe data :of .TablezIII, Data was secured by acid treatingthe partially oxiidized .stock using 1% 1b.: of acid .per gallon. The :product was testedby adding 10% of-t-heacid treated stock to a Southern .CaliforniaRegular Diesel base stock having a tcet'ane number value of 35. Cetanernumbers were determinedseventytwo hours after blending.

The'acid treated oil is'preferably washed with water after the last acid treatment to remove excess acid, is then washed with dilute caustic until neutral, and finally with water till salt and caustic free. It is preferable to use a 10% excess of 5% aqueous caustic over that required for neutralization for "this wash. Stronger caustic destroys the active oxygen components present and an appreciably larger'excess of caustic is also detrimental to the final. product. 7 Q

When the oil feedstock chosen for oxidation is suitable for use as .a Diesel "fuelfthe "product -is now an improved Diesel fuel and is ready for use. If, however the oil feed stock selected is not a suitable Diesel fuel, as forinstance by reason of its low boiling rangeyor if the object is to produce a blending agent Whichmay be added we Diesel fuel stock to increase the cetane number, the acid treated oil maybe added "to a base stock in an amount to produce a fuel having the desired cetane number.

It is frequently desirable, however, to utilize this product as a blending agentina more conc'entratedform, andin such cases the active octane-improving component isconcentrated before blending. The concentration step may be utilized either prior to or subsequent to the treatment with acid. Any method which is capable of concentratingthe jdesired oxidized hydrocarbon is adaptable to the practice of this modification of the process of this invention. For example, the oxidized hydrocarbons may be concentrated by distillation, or by other suitable means, for example, by solvent "extraction or by adsorption fractionation. In many "cases it will befound preferable to concentrate by distillation, and this method is illustratedand more fully described, althoughit is'tobe understood other methods "are equally applicable. Ordi- 'narily, it is preferable to concentrate this material by-removing the lower boiling unoxidize'd hydrocarbons from the mixture. "This-distillation is preferably carried out until only about 20% of the original volume remains in thgstill; however, this residue may vary between about 5% and 40% of the original charge, depending on conditions of previous treatment and-expected uses. The more orless'removed con= tains substantially-only inert or non cetane-improving hydrocarbons andmay be *recycledto the oxidation step of the process or :may -be otherwise utilized or discarded. The bottoms remaining in the still may suitably contain of the order of 40% of the initially partially ox'idlzed oil and contains' in wig-my concentrated described above and the concentration step of the process, the oxidized concentrated on will have an oxygen factor of not greater than .600, and preferably less than 300. It has been found that this concentration by distillation may best be carried on at a subatmospheric pressure of between mm. of mercury and atmospheric pressure and especially at about 30 mm. pressure. The optimum pressure is determined by the properties of the charging stock being concentrated. In general, a higher pressure is usable with a lighter charging stock. The term perature desirably is maintained below 350 F., preferably below 250 F. and especially of the order of 200 F.

Under some conditions of operation, it is preferable to concentrate the octane-improving components of the partially oxidized oil before the acid treatment. In this case the cetaneimproving compounds are concentrated as before by subjection of the partially oxidized stock prior to the acid treatment, to distillation, solvent extraction, or adsorbent fractionation. When distillation is used, fractionation preferably is carried out in the manner and to the extent outlined above. The more volatile com ponent which is removed can be recirculated to the oxidation step of the process or discarded. The bottoms remaining in the still contain oxygenated compoundsand exhibit an increased oxygen factor of at least 1000, preferably about 3000 to 7000 or even to 15,000. Concentration by distillation is carried out under conditions of temperature and pressure similar to those outlined above for concentration of acid treated oil.

The concentrated product is then acid treated as before, except a correspondingly greater amount of acid per gallon of stock is used to give a final product having an oxygen factor not greater than 20% of the oxygen factor of the concentrate, preferably below 600, and more suitably less than about 300.

Although a distinct two step process of oxidation and acid treatment has been described and is regarded as preferable, it is also considered within the scope of this invention to effect the partial oxidation and acid treatment concurrently in the same treating vessel and consequently produce the desired octane-improv ing product in one step, namely, partial oxidation of the charging stock in the presence of the acid to give the above-described product.

The acid treated concentrated oxidized oil produced either by acid treatment of the .unconcentrated stock followed by distillation or by acid treatment of the concentrated stock may be I used as a cetane-improving additive inordinary Diesel fuel in amounts between about 0.2% to 25% of the base fuel desirably between about 1% and and especially about 2% to 8% of the base fuel. 7

The Diesel fuels of this invention may also contain additional additives in some cases. For example, ordinary accelerators or primers may be added to the finished product aswell as antioxidants when desirable.

In one mode of operation, the invention may be carried out as exemplified in the how diagram of the appended drawing. Selected hydrocarbons adapted as previously described for the preparation of the improved injection engine .fuelof 8 this invention are fed via valve controlled line I to feed tank 2. These oils are then passed via valve controlled line 3 to oxidizer 4 where air enters via line 6, is dispersed by porous plate 1 and contacts the body of oil in the oxidizer. Oxidizer 4 is maintained at optimum oxidizing conditions to give controlled aeration of oil; re-

sidual gas and volatile hydrocarbon products leave the oxidizer via valve controlled line.8 through a cooling and condensing unit 9 and enter separator H) where the mixture is separated. Gas and uncondensed vapors are re: moved via line H. A water layer is removed via valve controlled line 12 and a hydrocarbon layer is removed at an intermediate point and recirculated to oxidizer 4 via valve controlled lines l3 and 3. It is sometimes advantageous to recirculate the main body of oil in oxidizer 4 by passing oil via a closed circuit including valve controlled lines l4, l5 and 3 (and suitable pumping means not illustrated). Or in some instances two or more oxidizers in series may be substituted for oxidizer 4 in which case the oil is circulated from the first oxidizer to subsequent oxidizers and is withdrawn from the last oxidizer in the series. When the oil has been treated to the degree desired as measured by the oxygen factor and neutralization number of samples withdrawn at suitable intervals, the treated oil is withdrawn from oxidizer 4 via valve controlled line' I4, is rapidly cooled with water from line H, and the cooled mixture is fed to agitator I8 via line [8. The partially oxidized oil is washed with water from line and then with dilute aqueous caustic solution from line 22. Spent aqueous solutions are withdrawn via valve controlled line 23. The partially oxidized caustic-scrubbed oil may then be passed via valve controlled line 24. to acid treato'r where it is treated with a strong acid from line 2'! under the conditions previously described, and then with water from line 28. Spent aqueous layer is removed via valve controlled line 29. The acid treated oil may then be fed via valve controlled lines and 32 to storage tank 33. If a more concentrated additive is desired,

the acid-treated oil may be fed via valve controlled lines 34 and 35 to a concentrator such as fractionating or distilling column 37 where the relatively volatile inert components are removed via line 38 and valve controlled lines 39 and l to feed tank 2 for recirculation through the system or are removed from the system via valve controlled line 40. Column 31 may be provided with conventional heating and refluxing means not illustrated. Concentrated, acid-treated oil constituting the desired octane-improving product, is removed via line 4! and valve controlled line 42 to storage tank 45.

Alternatively, the partially oxidized hydrocarbons may be concentrated prior to the acid treat? ment. In the practice of this embodiment of the invention, the caustic washed partially oxidized oil may be passed from agitator I 8 via valve controlled lines 24, 43 and 35 to concentrator 31 where the volatile components are removed via line 38 as before. The concentrated oxygen-containing fraction is then passed via line 4| valve controlled lines 44-and 24 to acid treator 25 where this concentrated oxygen-containing product is treated with acid as before but with increased quantities of acid corresponding to the increase in concentration of the feed. The concentrated, acid-treated product is then passed via valve controlled lines 30, 32, 46 and 42 to storage tank 45.

assesse- Th'e'practice of" the invention is further shown by -thefollowing specificexample's:

Example 1'.--700 cc. of Stoddard distillate, w-hich'after washingwith-one-half pound of 96% sulfuric acid per gallon, was relatively free from asphaltic and resinousmaterials and from large proportions of aromatic ring compounds, had a:

gravity of 46.4 API; boiled Within the range of 310 F. and 364 F., and had a cetane i'lumlcier operation had an oxygen factor of-801 and cetane number of 77. This product was washed with a ten per cent excess of aqueous caustic to give a product having a neutralization number of 1. This neutralized, partially oxidized; oil was then treated with one-quarter pound of"75% sulfuric acid per gallon of oil added in five dumps over a period of fifteen minutes at a temperature of about 75 F. This partially oxidized product had an oxygen factor of 98, a neutralization number of. 0.04, and a cetane number of 65.5, and constituteda highly desirable Diesel motor fuel for use as such or in a blend with other lower quality components. For example, when 5% of this partially oxidized acid treated product was added to an untreated automotive waxy Diesel fuel base having a cetane number of 42, the cetane number of the blended fuel was raised to 47.7.

The foregoing process example covering oxidation and acid treating steps illustrates the practice of the invention by a procedure wherein a concentrating step is not employed.

Example 2.-The acid treated, partially oxidized oil produced in Example 1 is distilled at 5 mm. of mercury pressure and 130 F. until 80% of its'volume has beenremoved. The vaporized portion had an oxygen factor of 13 and a neutralization number of less than 0.005; while the concentrate remainingin the still had an oxygen factor of 670 and a neutralization number of 0.033. Three per cent of this concentrated product was added to on untreated. waxy automotive Diesel base fuel boiling within the range of 340 F. to 576F. and having a cetane number of 41.1. The cetane number of this blended fuel after sixteen days of storage was 52.4. I

Evmmple 3.'700 cc. of the same acid washed Stoddard distillate as used in Example 1 was fed to-the oxidizing reactor. 18 cc. of seedstock. was addedand' the mixture air-blown for three hours at 300 F. using an air rate of two volumes per volume of oil per minute. The resultingproduct had an oxygen factor of 1175' and neutralization number of 11. This partially oxidized product was treated with one-quarter pound of 75% sulfuric-acidper gallon for fifteen minutes at 70 F.

The acid treated product wasrvashed with 5% caustic and water and had an oxygen factor of" 164 and a neutralization number-M001. The

washed, acid treated product was distilled at 5' mm; of mercury pressure and 122 F. until twenty concentrated product was blended with an un treated waxy'automotive Diesel base having a cetane number of 41.1. After sixteendays"Stor 1'0 age this blend 3 showed a cetane number of 50.9 or an increase in cetane number of 9.8.

Example 4.'-A Stoddard distillate similar to that used-in Examplel was oxidized and caustic washed as outlined in Example 1. 17% of this partially oxidized product was blended with an automotive Diesel -fuelboiling within the range of 308 F. to 578"F. and having a chart cetane number'of 42'. This blended stock having' an. oxygenfa'ctor of 153 was then treated with onequarter pound of 93% acid per gallon of stock at abouti'70 'F. The finished stock had an oxygen factor of2;2 and acetane number of 50.5.

Example 5.A- Stoddarddistillate similar to that used in Example l was air-blown and caustic washedasinExample 1 and thereafter exhibited an oxygen factor of 839 and a neutralization number of .12. This partially oxidized product wasdistilled: at 30' mm. pressure and a t'em perature under-200 .F. to separate the higher boiling fraction as a concentrate constituting Two per cent of this concentrated product having an' about1l2.'5%= of the original liquidvolume.

oxygen factor of 6240 was then blended in a Southern. California Regular refined distillate boiling within'the'range'of 388 F. to 656 F. and" having a'cetane number of' 41. After forty-eight" hours storage, this blend had a cetane number 01648.2. I I

Example: 6.A Stoddard distillate similar to that employed in Exar'nplel' was oxidized, neutralized', and, concentrated as in Example 5. One

portion of the concentrate was treated with one--' quarter pound of sulfuric acid pergallon at" 77F. for fifteen minutes and a second portion was treated withone and one-half pounds of 75 sulfuricacid per gallon at 77F. for twenty min utesiw The two products had oxygen factors of 3920 and 840, respectively. Two per cent of each of these products was: added to anautomotive base fuehhaving'a'cetane number of 40.9. After ninety-six hours of storage-the blended fuels had cetane numbers'of 49.1 and 50.8, respectively.

We claim:

1. A process of preparing an improved injec tion engine fuel which comprises subjecting a petroleum distillate which is predominantly saturelatively free of asa phaitic and resinous f materials to treatment'at 200 .to 400 F. in liquid phase with an oxygencontaining gas to produce a partially oxygenated rated hydrocarbons and oil having substantial proportions of chemically combined reactiveoxygen directly measurable in terms of the oxygen factor of the said fuel and exhibiting a generally proportional increased cetane number value, and contacting said result ant oxygenatedoil witha strongly acidic reagent at a: sufiicientlylow temperature of below about and less corrosion-producing oxygenated oil have ing a reduced oxygen factor, said strongly acidic reagent being selected from the group consisting of sulfuricacid, nitric acid, phosphoric acid and hydrochloric acid. I 2. The processor claim 1 wherein said petroleum'di'stillatehas an ASTM 50% boiling point within. the range 325 'to 650 F. v

3-; Theprociessbf claim lwhereinsaidfpetrole um distillate boils within the range 200 to 4% The process ofcla'ir'n lwher'iri the acid 00h accrues ll tacting step is carried out'at a temperature below 95 F. and with at least 0.1 pound of acidic reagent per gallon of partially oxygenated oil.

5. The process of claim 1 wherein said acidic reagent is a relatively concentrated aqueous solution of sulfuric acid.

6. A process of preparing an improved injection engine fuel which comprises subjecting a petroleum distillate relatively free from asphaltic and resinous materials and from large proportions of aromatic ring compounds to treatment at 200 to 400 F. in liquid phase with an oxygencontaining gas to produce a partially oxygenated oil having substantial proportions of chemically combined reactive oxygen directly measurable in terms of the oxygen factor of the said fuel and exhibiting a generally proportional increased cetane number value, and converting a substantial proportion of the chemically reactive oxygencontaining components of said oxygenated oil to oxygenated compounds having a reduced sensitivity to the oxygen factor test by contacting said partially oxygenated oil with a strongly acidic reagent under mild conditions including a temperature of below 95 F. and a relatively short contact time of less than about 90 minutes whereby oxygen factor sensitive oxygenated compounds are converted to more stable and less corrosionproducing oxygen factor insensitive oxygenated compounds which are effective to improve the cetane number of the fuel, said strongly acidic reagent being selected from the group consisting of sulfuric acid, nitric acid, phosphoric acid and hydrochloric acid.

7. A process of preparing an improved'injection engine fuel which comprises the steps of subjecting a petroleum distillate to a liquid phase oxidation treatment with an oxygen-containing gas at a temperature within the range of'200 F. to 400 F. and for a period of time suflicient to produce an' oil having an oxygen factor higher than about 250, concentrating said oxidized oil by means of fractionaldistillation at a tempera ture below 350 F. at a pressure between mm. of mercury and atmospheric and for a length of time sufficient to volatilize between 60 and 95% of said oxidized oil, thereby producing a residue having an oxygen factor of at least 1000, and contacting said residue with between 0.1 and 1 pound of a strongly acidic reagent per gallon of said residue at a temperature below about 95 F. for a relatively short time of less than about 90 minutes to reduce the oxygen factor of said residue to less than about of its original value, said strongly acidic reagent being selected from the group consisting of sulfuric acid, nitric acid, phosphoric acid and hydrochloric acid.

8. A process of preparing a relatively stable cetane-improving oxygenated oil which comprises contacting partially oxygenated hydrocarbon oil containing chemically combined reactive oxygen in sufficient proportions to give an oxygen factor of at least 250 and having a high cetane number value with a strongly acidic reagent at a temperature below 150 F. for a period less than 90 minutes to convert a substantial proportion of said partially oxygenated hydrocarbon oil to a relatively stable oxygenated oil of substantially reduced sensitivity to the oxygen factor test and having a high cetane number value, said strongly acidic reagent being selected from the group consisting of sulfuric acid, nitric acid, phosphoric oxygenated and partiallyoxygenated hydrocarbon compounds containing reactive oxygen meas-z urable in terms of the oxygen factor test and exhibiting a correspondingly high octane number value which comprises treating said mixture with a concentrated aqueous solution of sulfuric acid under mild conditions including a temperature of below 150 F. anda relatively short contact time of less than about 90 minutes to convert said original oxygenated compounds to more stable.

and less corrosion-producing oxygenated compounds having a high cetane number and a substantially reduced oxygen factor, and separating the acid treated partially oxygenated from the non-oxygenated compounds present in the mix ture to produce a concentrate of the relatively stable partially oxygenated hydrocarbons.

10. The process of claim 9 wherein in the acid contacting step there is used a small amount of acid less than l.pound per gallon of said mixture of non-oxygenated and partially oxygenated hydrocarbon compounds.

11. A process-of producing an improved Diesel fuel component from a mixture containing nonoxygenated and oxygenated hydrocarbon compounds containing reactive oxygen measurable in terms of the oxygen factor test and exhibiting a correspondingly high cetane number value which comprises separating non-oxygenated hydrocarbons from said oxygenatedhydrocarbons to produce a concentrate of the latter, and contacting said concentrate with a strongly acidic reagent under mild conditions including a temperature of below 150 F. and a relatively short contact time.

of less than about 90 minutes to convert said oxygenated hydrocarbons to more stable oxygenated hydrocarbons having a high cetane number value and a reduced oxygen factor, said strongly acidic reagent being selected from the group consisting of sulfuric acid, nitric acid, phosphoric acid and hydrochloric acid.

12. A process of preparing an improved injec tion fuelwhich comprises treating a petroleum distillate with an oxygen-containing gas at a temperature within the range of 250 F. to 350 F. and for a period of time sufiicient to produce a partially oxidized oilhaving an oxygen factor higher than about 250, and contacting said partially oxidized oil at a temperature below about 95 F. with a strongly acidic reagent for a rela tively short time of less than about 90 minutes to reduce the oxygen factor of said oil to below about 20% of its original value, whereby the product has a relatively high-cetane number and is relatively stable,- said strongly acidic reagent being selected from the group consisting of sulfuric acid, nitric acid, phosphoric acid and hydrochloric acid.

13. A'process of preparing an improved injection fuel which comprises the steps of subjecting a petroleum distillate boiling within the range 200 F; to 450 F. and relatively free from asphaltic and resinous'materials and from large pro- ;,portions of aromatic ring compounds to a liquid phase oxidation treatment with an oxygen-containing gas at a temperature within the range of 200 F. to 400 F. and for a period of time sufficient to produce an oil having an oxygen. factor .higher than about 250, contacting the resulting oxygenated oil with 50 to 90% sulfuric acid in an amount of 0.1 to 0.75'pound of said acid per gallon of said oxygenated'oil at a temperature of 50 to F. and for a period of less than minutes,

75 thereby producing a more stable and less corrosion-producing oxygenated oil having a substantially lowered oxygen factor, treating said oxygenated oil with controlled amounts of weak caustic solution to preferentially 'remove acidic material, and concentrating said caustic-treated oxygenated oil by means of fractional distillation at a temperature below 350 F. at a pressure between mm. of mercury and atmospheric and for a length of time suflicient to volatilize between 60 and 95% of said oxygenated oil whereby there is obtained a concentrate of said relatively stable cetane-improving oxygenated oil.

14. A Diesel type motor fuel component comprising as the active ingredient a liquid oxygenated hydrocarbon conversion product of treatment of partially oxygenated hydrocarbons containing chemically combined reactive oxygen sufficient to give a relatively high oxygen factor and having a high octane number with a strongly acidic reagent selected from the group consisting of sulfuric. nitric, phosphoric and hydrochloric acids under mild conditions of a low temperature below about 150 F. and a short contact time of less than about 90 minutes, said produce being relatively stable, relatively non-corrosive, soluble in hydrocarbons in the Diesel fuel range and having a relatively low oxygen factor and a high cetane number.

15. An improved Diesel type motor fuel comprising a solution in hydrocarbons within the Diesel fuel boiling range having a relatively low cetane number, of a mildly treated acid conversion product of amixture of oxygenated hydrocarbons containing reactive oxygen measurable in terms of the oxygen factor test and having a correspondingly high octane number value, the active octane-improving portion of said conversion product being relatively stable and soluble in hydrocarbons in the Diesel fuel range and having an oxygen factor below 300, said mild acid treatment being ata low temperature of less than 150 ,F. and a shortcontact time of less than about minutes and with a strongly acidic reagent selected from the group consisting of sulfuric, nitric, phosphoric and hydrochloric acids.

GEORGE H. DENISON, JR. JOHN E. HANSON.

REFERENCES CITED The, following references are of record in the file of this patent:

UNITED STATES PATENTS 

11. A PROCESS OF PRODUCING AN IMPROVED DIESEL FUEL COMPONENT FROM A MIXTURE CONTAINING NONOXYGENATED AND OXYGENATED HYDROCARBON COMPOUNDS CONTAINING REACTIVE OXYGEN MEASURABLE IN TERMS OF THE OXYGEN FACTOR TEST AND EXHIBITING A CORRESPONDINGLY HIGH CETANE NUMBER VALUE WHICH COMPRISES SEPARATING NON-OXYGENATED HYDROCARBONS FROM SAID OXYGENATED HYDROCARBONS TO PRODUCE A CONCENTRATE OF THE LATTER, AND CONTACTING SAID CONCENTRATE WITH A STRONGLY ACIDIC REAGENT UNDER MILD CONDITIONS INCLUDING A TEMPERATURE OF BELOW 150*F. AND A RELATIVELY SHORT CONTACT TIME OF LESS THAN ABOUT 90 MINUTES TO CONVERT SAID OXYGENATED HYDROCARBONS TO MORE STABLE OXYGENATED HYDROCARBONS HAVING A HIGH CETANE NUMBER VALUE AND A REDUCED OXYGEN FACTOR, SAID STRONGLY ACIDIC REAGENT BEING SELECTED FROM THE GROUP CONSISTING OF SULFURIC ACID, NITRIC ACID, PHOSPHORIC ACID AND HYDROCHLORIC ACID.
 14. A DIESEL TYPE MOTOR FUEL COMPONENT COMPRISING AS THE ACTIVE INGREDIENT A LIQUID OXYGENATED HYDROCARBON CONVERSION PRODUCT OF TREATMENT OF PARTIALLY OXYGENATED HYDROCARBONS CONTAINING CHEMICALLY COMBINED REACTIVE OXYGEN SUFFICIENT TO GIVE A RELATIVELY HIGH OXYGEN FACTOR AND HAVING A HIGH CETANE NUMBER WITH A STRONGLY ACIDIC REAGENT SELECTED FROM THE GROUP CONSISTING OF SULFURIC, NITRIC, PHOSPHORIC AND HYDROCHLORIC ACIDS UNDER MILD CONDITIONS OF A LOW TEMPERATURE BELOW ABOUT 150*F. AND A SHORT CONTACT TIME OF LESS THAN ABOUT 90 MINUTES, SAID PRODUCE BEING RELATIVELY STABLE RELATIVELY NON-CORROSIVE, SOLUBLE IN HYDROCARBONS N THE DIESEL FUEL RANGE AND HAVING A RELATIVELY LOW OXYGEN FACTOR AND A HIGH CETANE NUMBER. 